In the production of bread, a mass of kneaded dough is prepared in a mixer, and the mass of kneaded dough is extruded as a continuous stream of kneaded dough by a pump and divided into a plurality of streams of kneaded dough through a kneaded dough dividing apparatus. Thereafter, each stream of kneaded dough is divided into small pieces necessary for bread baking.
A kneaded dough dividing apparatus is disclosed in U.S. Pat. No. 8,387,521. The kneaded dough dividing apparatus includes a divider having a dough inlet receiving one continuous stream of kneaded dough discharged from a horizontally extending screw extruder (pump) communicated with an opening at the lower end of a hopper receiving the above-described mass of kneaded dough. The divider discharges the received kneaded dough as two continuous streams of kneaded dough from two dough outlets positioned in bilateral symmetry at the downstream side of the dough inlet. A similar divider is connected at a dough inlet thereof to each of the two dough outlets of the first-mentioned divider. In this way, dividers are connected successively from the upstream side toward the downstream side to produce a required number of streams of kneaded dough. Each divider has an outlet control member adjusting the respective opening areas of the two dough outlets. The outlet control member reduces the opening area of one of the two dough outlets when enlarging the opening area of the other of the two dough outlets and reduces the opening area of the other dough outlet when enlarging the opening area of the one dough outlet, thereby allowing the total amount of kneaded dough discharged from the divider to be kept substantially constant, and hence enabling the pressure in the divider to be kept substantially constant, and thus allowing the quality of kneaded dough discharged from the divider to be kept constant.
However, it has been found that the kneaded dough dividing apparatus having the above-described divider is not necessarily satisfactory in terms of the quality of dough discharged therefrom from the viewpoint of obtaining dough of even more ideally uniform quality. That is, it has been found that the quality of kneaded dough is somewhat different for each dough outlet of the dough dividing apparatus discharging the dough. The quality of kneaded dough is considered to depend on various factors acting on the kneaded dough in the kneaded dough passage from the discharge from the screw extruder to the discharge from the dough outlets of the kneaded dough dividing apparatus. Therefore, it has been difficult to determine the cause of nonuniformity in quality of kneaded dough. In this regard, the present inventors have conducted various studies and, as a result, found that the cause of the quality nonuniformity of kneaded dough is the internal pressure conditions in the kneaded dough when extruded from the screw extruder. That is, kneaded dough is supplied from the hopper to the screw extruder, transferred rectilinearly through the screw extruder and extruded from an outlet directed at right angles to the transfer direction. Immediately before being extruded from the outlet, the kneaded dough, which has been transferred rectilinearly so far, is pressed against the terminating end surface of the screw extruder, and then turned at a right angle before being discharged from the outlet. Accordingly, the kneaded dough pressed against the terminating end surface is subjected to a high pressure, and the pressure applied to the kneaded dough decreases as the distance from the terminating end surface increases toward the hopper. Consequently, kneaded dough extruded from the outlet in the form of a laminar flow has a pressure gradient in a horizontal direction as seen in a cross-section thereof When such kneaded dough is received into the divider and discharged from the two dough outlets, being divided into right and left streams of kneaded dough, a difference is made between the internal pressures of the two streams of kneaded dough discharged from the dough outlets. The present inventors have found that the above-described pressure difference has an effect on the quality of each stream of kneaded dough discharged from the kneaded dough dividing apparatus.